The present invention relates to a lock, and more particularly to a numerical lock.
In the prior art, there are various kinds of locks been designed. One of them is a numerical lock which can be used without a key for convenience. The most known numerical locks are unable to be changed their combinations and are obviously undependable because of unique opened number which may be found out undesiredly. There still are other numerical locks which have changable combinations but rise structure complexity and cost.